1. Field of the Invention
The present invention relates generally to the field of seal members, and, more particularly, to an improved seal member which is adapted to contain leakage of fluid passing from a pressurized chamber between a wall opening and a penetrant rod portion passing therethrough.
2. Description of the Prior Art
Many forms of fluid-powered actuators have been heretofore developed. The most common of these has a piston slidably mounted within a cylinder. A rod typically penetrates an end wall of the cylinder and is connected to the piston, such that the piston and rod move together as a unit. Generally, the portion of the rod which is arranged within the piston end chamber will be exposed to a pressure greater than the distal end of the rod, which is arranged on the other side of the wall penetrated by the rod. Because of the pressure differential which may be encountered across such wall, fluid will tend to leak from the piston end chamber between the wall opening and the penetrant portion of the rod passing therethrough. It has been known to provide resilient seals between the rod and the wall opening to substantially reduce the amount of fluid leakage therebetween. It has also been known to provide a closely-fitted rod through a wall opening having certain axially-spaced grooves in the marginal portion about the opening. This is known as a "laminar seal" because it has the characteristics of relatively-low, laminar leakage, and has a very long life.
However, in some situations, the actuator rod must operate in a cyclical or harmonic manner over long periods of time. In these applications, it would be desirable that the rod seal have an extremely long endurance life and substantially zero leakage. Typical elastomeric or plastic seals will not afford the required life, and closely-fitted, lapped, metal-to-metal seals, which can meet the life requirements, typically exhibit unacceptable rates of leakage.